Information Rates over Point-to-Point and Multi-user Wireless Channels with Energy and Delay Constraints

Abstract

In this thesis, we consider communication systems having energy, delay and reliability constraints. We characterize optimal communication rates achievable over these systems.

First we consider point-to-point communication setting. In this context, first, we characterize achievable rates for an energy harvesting point-to-point channel with additive Gaussian noise. These rates are shown to be close to the optimal rates under various assumptions on the system architecture. Next, we consider a non-energy harvesting, point-to-point block fading wireless channel with Gaussian noise, subjected to canonical peak and average power constraints. We characterize lower and upper bounds on the maximal channel coding rate with channel state information at the transmitter and the receiver, at a given codeword length and average probability of error. The bounds characterize back-off from the water-filling capacity in the finite block length regime. Subsequently, we extend the finite block length results derived for the non-energy harvesting channel, to the case where the transmitter is energy harvesting. Next, we consider multi-user communication scenario. In this setting, first, we consider a Gaussian multiple access channel with energy harvesting transmitters. We obtain the capacity region of the channel with transmitters having infinite energy buffer. In addition, with transmitters assumed to have finite energy buffers, we characterize achievable rate regions.

Next, we obtain inner bounds to the ergodic capacity region of a block fading Gaussian multiple access channel, with finite codeword length, non-vanishing average error probability and peak power constraint on the codewords. Subsequently, we consider a fading Gaussian broadcast channel under the assumption that both the transmitter and the receivers harvests energy and the receivers treat the transmitter as a radio frequency energy source. This corresponds to the paradigm of simultaneous wireless information and power transfer. In this scenario, we characterize the fundamental limits of simultaneous wireless information and power transfer under a minimum-rate constraint. Finally, we consider an energy harvesting, fading Gaussian multiple access channel and the receivers treat transmitter as an radio-frequency energy source. In this setting as well, we characterize the information theoretic limits under a minimum-rate constraint at each user.